// when the DOM is ready...
$(document).ready(function () {

var $panels = $('#slider .scrollContainer > div'); // collection of slider content
var $container = $('#slider .scrollContainer');    // container

// if false, we'll float all the panels left and fix the width 
// of the container
var horizontal = true; // horizontal or vertical scrolling

// float the panels left if we're going horizontal
if (horizontal) {
  $panels.css({
    'float' : 'left',
    'position' : 'relative' // IE fix to ensure overflow is hidden
  });
  
  // calculate a new width for the container (so it holds all panels)
  $container.css('width', $panels[0].offsetWidth * $panels.length); // offsetWidth: browser's client area without the vertical scrollbar
}

// collect the scroll object, at the same time apply the hidden overflow
// to remove the default scrollbars that will appear
var $scroll = $('#slider .scroll').css('overflow', 'hidden');

// apply our left + right buttons: add image
$scroll
  .before('<img class="scrollButtons left" src="img/back-arrow.png" />')
  .after('<img class="scrollButtons right" src="img/forward-arrow.png" />');

// handle nav selection
// add selected class
function selectNav() {
  $(this)
	  .parents('ul:first') // find the first UL parent
	    .find('a') // find all the A elements
	      .removeClass('selected') // remove from all
	    .end() // go back to all A elements
	  .end() // go back to 'this' element
	  .addClass('selected');
}

// bind the navigation clicks to update the selected nav:
$('#slider .navigation').find('a').click(selectNav);

// go find the navigation link that has this target and select the nav
/*
 * This is achieved using event binding. When the scroll plugin completes 
 * it’s effect, it will call our trigger function. The trigger function 
 * will receive the ID of the element it has just shown, and search for 
 * the navigation item whose href’s hash matches the ID.
 */
function trigger(data) {
	// within the .navigation element, find the A element
	// whose href ends with ID ($= is ends with)	
	var el = $('#slider .navigation').find('a[href$="' + data.id + '"]').get(0);
 
	// we're passing the actual element, and not the jQuery instance.
	selectNav.call(el); // this = el, this.selectNav
}

// hash on URL, trigger scrollerComplete function
if (window.location.hash) {
  trigger({ id : window.location.hash.substr(1) });
} else {
  $('ul.navigation a:first').click();
}

// offset is used to move to *exactly* the right place, since I'm using
// padding on my example, I need to subtract the amount of padding to
// the offset.  Try removing this to get a good idea of the effect
var offset = parseInt((horizontal ? 
  $container.css('paddingTop') : 
  $container.css('paddingLeft')) 
  || 0) * -1;

//scrollTo options
var scrollOptions = {
  target: $scroll, // the element that has the overflow
  
  // can be a selector which will be relative to the target
  items: $panels,
  
  navigation: '.navigation a',
  
  // selectors are NOT relative to document, i.e. make sure they're unique
  prev: 'img.left', 
  next: 'img.right',
  
  // allow the scroll effect to run both directions
  axis: 'xy',
  
  onAfter: trigger, // our final callback
  
  offset: offset,
  
  // duration of the sliding effect
  duration: 500,
  
  // easing - can be used with the easing plugin: 
  // http://gsgd.co.uk/sandbox/jquery/easing/
  easing: 'swing'
};

// apply serialScroll to the slider - we chose this plugin because it 
// supports// the indexed next and previous scroll along with hooking 
// in to our navigation.
$('#slider').serialScroll(scrollOptions);

// now apply localScroll to hook any other arbitrary links to trigger 
// the effect
$.localScroll(scrollOptions);

// finally, if the URL has a hash, move the slider in to position, 
// setting the duration to 1 because I don't want it to scroll in the
// very first page load.  We don't always need this, but it ensures
// the positioning is absolutely spot on when the pages loads.
scrollOptions.duration = 1;
$.localScroll.hash(scrollOptions);

});